Effect of microstructure on dynamic shear localisation in Alloy 718

Johansson, J.; Persson, Christer; Testa, Gabriel; Ruggiero, Andrew; Bonora, Nicola; Colliander, Magnus Hörnqvist

doi:10.1016/j.mechmat.2017.03.020

Cited by 23 publications

(19 citation statements)

References 28 publications

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“…The solution treated Inconel 718 displays more distinct strain hardening than that of the aged Inconel 718. The shear localization at the base end of the flat hat-shaped sample initiates earlier than the hat ends, and the similar phenomenon has been reported in previous studies [21,25]. It can be seen from the shape of the Inconel 718 sample that the base end has less constraint to the shear deformation than that of the hat end.…”

Section: Discussionsupporting

confidence: 87%

“…It is worth noting that the shear localization may occur before the stress peaks. Johansson [21] et al compared the dynamic mechanical properties of Inconel 718 with the results of a metallographic examination from the dynamic shear tests. They suggested that the load drop may be delayed by the formation of the ASB and does not occur until the ASB is completely formed.…”

Section: Discussionmentioning

confidence: 99%

“…The needle like δ phase marked with arrows in Fig. 4(d) are pinned on the grain boundaries, thus suppressing the grain growth and reducing the grain size [21]. The δ phase in the solution treated Inconel 718 could improve the impact toughness as well as the plasticity.…”

Section: Microstructure With Different Heat Treatmentsmentioning

confidence: 99%

“…The observations showed the similarities between the two shear localization processes, such as the equiaxed nanocrystalline grains and the evident shear texture. Furthermore, they explored the shear localization in Inconel 718 top-hat samples with different heat treatments at a global strain rate of 1500 s −1 [21]. Both dynamic shear tests and numerical simulations have been utilized to study the effect of heat treatment condition, grain size and local geometry on shear band formation.…”

Section: Introductionmentioning

confidence: 99%

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Effects of different heat treatments on the dynamic shear response and shear localization in Inconel 718 alloy

Song¹,

Hu²,

Zhang³

et al. 2018

Materials Science and Engineering: A

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The effects of different heat treatments on the dynamic shear response and the adiabatic shear localization characteristic of Inconel 718 alloy (Inconel 718) are studied by the flat hat-shaped sample subjected to the Split Hopkinson Pressure Bar (SHPB) loading. The microstructures of the concentrated shear zone are examined by optical microscopy (OM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), and Vickers micro-hardness tests, respectively. The results indicate that the aged Inconel 718 with higher yield strength and lower strain hardening rate is easier to form an adiabatic shear band (ASB) than that of the solution treated Inconel 718 under dynamic shear loadings. Meanwhile, it has been found that the δ phase plays an important role in inhibiting the shear localization of the solution treated Inconel 718. Little plastic deformation occurs in the region adjacent to the ASB in the aged Inconel 718, whereas significant plastic deformation occurs in a certain width area around the ASB in the solution treated Inconel 718.

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Microstructure With Different Heat Treatmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of different heat treatments on the dynamic shear response and shear localization in Inconel 718 alloy

Song¹,

Hu²,

Zhang³

et al. 2018

Materials Science and Engineering: A

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“…In fact, at that time, an overwhelming body of evidence suggesting that plastic deformation is necessary to nucleate void from particles, either by particle breaking or by particle matrix debonding, had been already available. For voids developing along grain boundaries, when grain boundary particles are absent, blocked slip bands, triple points, or other boundary irregularities may drive void nucleation and drive shear localization . Goods and Nix found that strain for void nucleation in pure silver is as large as approximately 2/3 of fracture strain.…”

Section: Introductionmentioning

confidence: 99%

Stress triaxiality effect on void nucleation in ductile metals

Testa

Bonora

Ruggiero

et al. 2020

Fatigue Fract Eng Mat Struct

Self Cite

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The stress triaxiality effect on the strain required for void nucleation by particle-matrix debonding has been investigated by means of micromechanical modelling. A unit-cell model considering an elastic spherical particle embedded in an elastic-plastic matrix was developed to the purpose. Particle-matrix decohesion was simulated through the progressive failure of a cohesive interface. It has been shown that the parameters of matrix-particle cohesive interface are correlated with macroscopic material properties. Here, a simple relationship for the maximum cohesive opening at interface failure as a function of material fracture toughness and yield stress has been derived. Results seem to confirm that, increasing stress triaxiality, the strain at which void nucleation is predicted to occur decreases exponentially in a similar way as for fracture strain. This result has substantial implications in modelling of ductile damage because it indicates that if the stress triaxiality is high enough, ductile fracture can occur at plastic strain lower than that necessary to nucleate damage for moderate or low stress triaxiality regime. K E Y W O R D Smicromechanics, stress triaxiality, void nucleation, α-iron

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Gradient‐enhanced damage growth modeling of ductile fracture

Larsson

Erturk

2021

Numerical Meth Engineering

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We present a gradient-enhanced damage model for ductile fracture modeling, describing the degraded material response coupled to temperature. Continuum thermodynamics is used to represent components of the energy dissipation as induced by the effective material response, thermal effects, and damage evolution. The viscoplastic Johnson-Cook constitutive model serves as prototype for the effective material. The continuum damage evolution of Lemaitre type is focusing the degradation of the shear response, eventually leading to ductile shear failure. A novel feature is the damage-driving dissipation rate, allowing for elastic and plastic components separated by a global damage threshold for accumulation of inelastic damage-driving energy. In the application to a dynamic split-Hopkinson test and two quasi-static tensile tests, the gradient damage model is compared with the corresponding local model. For isothermal conditions, the examples show that both damage models exhibit mesh convergent behavior when using the global damage threshold. K E Y W O R D Scontinuum damage, damage-driving energy, ductile fracture, gradient damage, mesh convergence INTRODUCTIONFinite element modeling and simulation of machining processes relates strongly to the ability of the constitutive model to represent localized shear and chip form in the vicinity of the cutting tool. [1][2][3] These phenomena can be modeled using thermoviscoplasticity combined with continuum damage to describe ductile failure for the representation of serrated chip formation. 4 The major ductile failure scenario is that failure initiates with void nucleation/microcrack development that coalesce, first on the microstructural level, eventually forming a macroscopic crack or a diffuse damage zone on the macroscale. In many engineering fields, for example, machining and lightweight design, ductile failure is an important phenomenon to account for. It is of vital importance to efficiently and accurately control the fracture process. To achieve this, finite element based continuum damage modeling needs to correctly predict important features such as stress state, damage/initiation/propagation, load carrying capacity of the structure associated with the damage patterns.From the key work of Gurson, 5 ductile damage is attributed to growth of microvoids, whose evolution is formulated in (local) Gurson-type plasticity models. Various formulations of the Gurson-based void growth have been considered, for existing and nucleated voids including the morphology of the voids, for example, Needleman and Tvergaard, 6 Pardoen and Hutchinson. 7 In the FE-application, the void formation is assumed to coalesce into fracture surfacesThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Effect of microstructure on dynamic shear localisation in Alloy 718

Cited by 23 publications

References 28 publications

Effects of different heat treatments on the dynamic shear response and shear localization in Inconel 718 alloy

Effects of different heat treatments on the dynamic shear response and shear localization in Inconel 718 alloy

Stress triaxiality effect on void nucleation in ductile metals

Gradient‐enhanced damage growth modeling of ductile fracture

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